Lectures and seminars Guest seminar - Dr. Madhu Srinivasan, University of Oxford
Monday, February 9 at 3pm in room D1012, Biomedicum. Title: “DNA catenation is essential for Sister Chromatid Cohesion”.
Welcome to guest seminar by Dr. Madhu Srinivasan from the University of Oxford
Date & Time: Monday, February 9 at 15:00 – 16:00.
Place: D1012, Biomedicum.
Speaker: Madhu Srinivasan, University of Oxford.
Title: “DNA catenation is essential for Sister Chromatid Cohesion”
From S phase to mitosis, sister chromatids are held together to ensure they attach correctly to the spindle. This linkage, called sister chromatid cohesion, arises from entrapment of sister DNAs inside a ring-shaped protein complex called cohesin. DNA catenations that arise naturally during replication could also tether chromatids, but their functional role in cohesion has never been established. Here, using the tractability of budding yeast, we have discovered that DNA catenation plays an essential role in mitotic cohesion. Selectively removing catenations causes catastrophic cohesion loss under spindle tension, delays chromosome biorientation, and increases chromosome mis-segregation, even when cohesin rings remain intact. We show that the catenations are protected and spatially confined to peri-centromeres by cohesin, where they play an essential role in counteracting spindle forces that would otherwise pull apart chromosomes. Our findings revise the textbook model of cohesion by establishing DNA catenation as an integral, force-resistant mechanism ensuring accurate chromosome segregation.